From 8d58881b995904bf8b150dae69be0829f832e7be Mon Sep 17 00:00:00 2001
From: Bart Van Assche <bart.vanassche@sandisk.com>
Date: Thu, 22 Sep 2016 14:20:54 -0700
Subject: scsi: Avoid that toggling use_blk_mq triggers a memory leak
This patch avoids that the following memory leak is triggered if
use_blk_mq is disabled after a SCSI host has been allocated by the
ib_srp driver and before the same SCSI host is freed:
unreferenced object 0xffff8803a168c568 (size 256):
backtrace:
[<ffffffff81620c95>] kmemleak_alloc+0x45/0xa0
[<ffffffff811bb104>] __kmalloc_node+0x1e4/0x400
[<ffffffff81309fe4>] blk_mq_alloc_tag_set+0xb4/0x230
[<ffffffff814731b7>] scsi_mq_setup_tags+0xc7/0xd0
[<ffffffff81469c26>] scsi_add_host_with_dma+0x216/0x2d0
[<ffffffffa064bef5>] srp_create_target+0xe55/0x13d0 [ib_srp]
[<ffffffff8143ce23>] dev_attr_store+0x13/0x20
[<ffffffff8125f030>] sysfs_kf_write+0x40/0x50
[<ffffffff8125e397>] kernfs_fop_write+0x137/0x1c0
[<ffffffff811d8c13>] __vfs_write+0x23/0x140
[<ffffffff811d92e0>] vfs_write+0xb0/0x190
[<ffffffff811da5b4>] SyS_write+0x44/0xa0
[<ffffffff8162c8a5>] entry_SYSCALL_64_fastpath+0x18/0xa8
Fixes: 9aa9cc4221f5 ("scsi: remove the disable_blk_mq host flag")
Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Martin K. Petersen <martin.petersen@oracle.com>
Cc: <stable@vger.kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
---
include/scsi/scsi_host.h | 5 +----
1 file changed, 1 insertion(+), 4 deletions(-)
(limited to 'include/scsi')
diff --git a/include/scsi/scsi_host.h b/include/scsi/scsi_host.h
index 0dee7afa93d6..7e4cd53139ed 100644
--- a/include/scsi/scsi_host.h
+++ b/include/scsi/scsi_host.h
@@ -771,12 +771,9 @@ static inline int scsi_host_in_recovery(struct Scsi_Host *shost)
shost->tmf_in_progress;
}
-extern bool scsi_use_blk_mq;
-
static inline bool shost_use_blk_mq(struct Scsi_Host *shost)
{
- return scsi_use_blk_mq;
-
+ return shost->use_blk_mq;
}
extern int scsi_queue_work(struct Scsi_Host *, struct work_struct *);
--
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